The kinematic preshaping of triggered self-adaptive linkage-driven robotic fingers

Abstract

Abstract. In this paper, the issue of the kinematic -as opposed to dynamic -preshaping of self-adaptive robotic fingers driven by linkages is discussed. A method to obtain designs of these fingers capable of various behaviours during their closing motions is presented. The method is based on using triggered passive elements in carefully selected joints of the finger and the selection or optimization of geometric parameters to obtain particular kinematic relationships between the motions of the phalanges. This method is very general and can be applied to any self-adaptive robotic finger in order to obtain many different types of closing motions. Examples given in this paper are focusing on two different preshaping motions, the first one aims at allowing pinch grasps while the second mimics a human finger. The fundamental aim of this paper is to show that various preshapings of self-adaptive fingers are possible, not just one, and to give two step-by-step examples.

Design and testing of a selectively compliant underactuated hand

“…Variable transmission-ratio devices were implemented in the designs of Takaki and Omata (2006) and Spanjer et al (2012), and variable preload devices are investigated in Aukes et al (2011). Willow Garage's "Velo 2G" gripper 6 uses spring preloads to maintain a position constraint which keep fingertips parallel to each other, similar to the linkage-based design discussed in Birglen (2011). Catalano et al (2012) designed a hand with stiffness and drive train selected to reflect identified "adaptive synergies", while allowing the hand to fail gracefully in the case of disarticulations.…”

A highly-underactuated robotic hand with force and joint angle sensors

“…To effectively apply the TPUA in robotic fingers, a feasible design must be considered with all parameters optimized regarding geometry, mechanics, and motion planning. While the mechanics of a linkage-driven self-adaptive finger is discussed in [12], this analysis demonstrates the mechanics of a tendon-based adaptive underactuated hand. As shown in Fig.…”

A highly-underactuated robotic hand with force and joint angle sensors

“…While the mechanics of a linkage-driven self-adaptive finger is discussed in [12], this analysis demonstrates the mechanics of a tendon-based adaptive underactuated hand. As shown in Fig.…”